Nadal pulls out of ATP Finals with injury

"I thought about my last match against John (Isner) in Paris", said Dimitrov, referring to another recent loss in which he wasted a match point.

"It is about the pain, I can not hold with enough power to keep playing". "I'm just very grateful to win that match, especially in that manner. It really doesn't make sense".

"My season's over", the Spaniard said.

"I know what I have to do", he said. "I know all the things that happened in the past when I had these things, and I know the treatment that I had to do". "I've done also a lot of work on and off the court". If the treatment works or not, we will see.

With Andy Murray away injured, Roger Federer and Rafael Nadal are the stand-out attractions at this week's tournament but there may be few contests as entertaining as this one, lasting two hours and 19 minutes.

The Belgian composed himself to hold and then earned three more match points but Nadal, showing incredible grit and playing right at the limit, saved all three to take it to another tie-break, which he won.

Nadal blamed the defeat on his recurring knee problem.

"Rafa is one of the strongest players mentally on the tour".

Back came Dimitrov, though, with a break to love and he made no mistake in the final game of the match, converting his third match point as Thiem fired long from the baseline. "It is so special to do it here".

With Rafael Nadal's withdrawal, there are still many scenarios for the Pete Sampras group players at the ATP Finals in London.

Dimitrov opened his charge in London with a determined 6-3 5-7 7-5 win over his Austrian counterpart, who is ranked two places higher in the rankings.

"I'm not going to lie - I was pretty nervous, my first match out here", he told reporters.

Thiem applied pressure in game eight but it came to nothing, however with Dimitrov serving for the match for a second time the Austrian finally found a way through to level the decider at 5-5.